The invention relates generally to electric vehicle power systems and more specifically to an adapter for connecting an on-vehicle battery charger with an electrical outlet wherein the adapter transmits certain electrical characteristics of the outlet to the charger.
Electric vehicle battery systems typically employ charging facilities with unique features and greater power transfer capabilities than most conventional electrical outlets. Therefore, specially adapted recharging stations are provided with power supply capability coincident with the recharge capability of the electric vehicle power system. Nevertheless, it is desirable to have the capability to recharge electric vehicles using either specially adapted charging facilities or standard wall outlets if such a charging facility is unavailable. The specially adapted charging facilities may deliver current at a rate of about 230 volts and 30 amps while a standard wall outlet delivers 120 volts and 12 amps.
It is desirable to produce an electric vehicle power system capable of being recharged anywhere in the world. One obstacle, however, lies in the different electrical services provided throughout the world. For example, the line voltage in the U.S. is 120 volts while in Europe it is 230 volts. Household-type appliances are known which transform the different outlet voltages to a common voltage to operate the appliance. However, in this method the power transfer capabilities of the outlets are not fully utilized. A special outlet is capable of handling a significantly higher current than a standard wall outlet and thus, a battery can be charged at a faster rate. If a battery charger attempts to charge through a standard wall outlet at the high current of a special outlet, current in excess of the ratings for the outlet and household wiring will flow thereby tripping a circuit breaker or blowing a fuse.
It is therefore desirable to provide an adapter that informs the battery charger of the electrical characteristics of the outlet, thereby allowing the charger to fully utilize the power capabilities of the outlet.